1. Field of the Invention
The present invention relates to a sensor cartridge for housing a sensor that is used for acquisition of living body numerical information, and a measuring device including such a sensor cartridge.
2. Description of the Related Art
Conventionally, in order to measure living body numerical information such as a blood glucose level, compact analytical sensors called biosensors are used. In general, a biosensor is a single-use device, and is set in a measuring device each time measurement is performed. After completion of measurement, the biosensor is then discarded together with a sample that has been measured. At the time of the next measurement, the user sets a new biosensor in the measuring device.
In general, biosensors are classified into biosensors using an electrochemical measurement method and biosensors using a colorimetric measurement method. Of these, the biosensors using an electrochemical measurement method (hereinafter, simply referred to as “biosensors”) ordinarily include an inlet for introducing a sample into the biosensors and two or more electrodes. A sample introduced from the inlet is transferred to a position where the sample comes into contact with these electrodes, using capillary action or the like. In addition, the electrodes are electrically connected to connection terminals provided on the outer surface of the biosensor. Because of this configuration, it is necessary for the user to bring the connection terminals of the biosensor into contact with the corresponding terminals of the measuring device in a reliable manner, at the time of setting the biosensor in the measuring device.
However, there is a problem in that a situation tends to arise where the biosensor, because of its small size, is set in a wrong orientation or is not set in a predetermined position in a reliable manner especially in the case where the user has poor eyesight. For this reason, a sensor cartridge to which a plurality of biosensors are mounted and a measuring device including such a sensor cartridge has been proposed.
JP H10-253570A, JP 2001-281199A, and JP 2003-215086A disclose sensor cartridges that function as a sensor feeding device for successively supplying biosensors to a measuring device. Furthermore, a large number of biosensors are formed in the shape of a plate, and have been housed in advance in a stacked state in a container constituting the sensor cartridge. Additionally, the sensor cartridge housing the biosensors is attached within the casing of a measuring device.
At the time of measurement, the biosensors housed in the sensor cartridge are pushed out one by one by an arm provided within the measuring device, and the biosensor that has been pushed out is placed in a measurement position. Further, once the biosensor has been placed in the measurement position, electrodes provided within the measurement apparatus are moved to terminals of the biosensor and are connected to the terminals, bringing about a state where a sample can be measured. Thereafter, a sample is supplied into the biosensor, and measurement is carried out. The measured living body information is displayed on a display screen of the measuring device.
After completion of the measurement, the used biosensor is pulled out, and discarded. Then, at the time of the next measurement, an unused biosensor housed in the cartridge is newly placed automatically. In this way, it is thought that using the sensor cartridge and measuring device disclosed in JP H10-253570A, JP 2001-281199A, or JP 2003-215086A greatly improves the convenience for the user since it allows the user to carry out multiple measurements by simply setting the sensor cartridge.
JP 2510702Y discloses a sensor cartridge that has the function of successively supplying biosensors, and that is configured to function as a measuring device on its own, not just as a feeding device. Specifically, the sensor cartridge disclosed in JP 2510702Y is internally provided with a plurality of biosensors that are arranged in series, and only the biosensor at the head is exposed from the casing of the sensor cartridge. In addition, the sensor cartridge is connected to an external measurement apparatus via a distribution cable.
When the user performs measurement by using the biosensor located at the head while holding the sensor cartridge by hand, the data acquired with that biosensor is sent to the external measurement apparatus via the cable. Upon completion of the measurement, the user manipulates a slider that is provided in the sensor cartridge to push the used biosensor out, and then discards the biosensor. This slider manipulation also brings about a state in which a new biosensor has been set.
The measuring device disclosed in JP H10-253570A, JP 2001-281199A, or JP 2003-215086A is required to have complex mechanisms such as a mechanism for delivering biosensors contained in the sensor cartridge and a mechanism for connecting the electrodes of the measuring device to the connection terminals of the biosensors. Therefore, the measuring devices disclosed in these documents have the problem of high manufacturing costs. The measuring devices also have a problem in that they are susceptible to failure due to their complex mechanisms.
Furthermore, since the connection between the electrodes of the measuring device and the terminals of the biosensors is established by moving the electrodes of the measuring device by using an arm or the like, the positioning of the arm or the like may become inaccurate due to degraded parts, the environment of usage, a bug in the control software, and the like. If the positioning becomes inaccurate, there may be cases when the measurement error becomes large, or measurement is impossible, resulting in the problem of not being able to perform stable measurements.
Furthermore, biosensors are expected to be more compact in the future, and the required positioning accuracy will increase accordingly. Therefore, it is thought that the above-described problem of not being able to perform stable measurements will become even more significant with the size reduction of biosensors.
On the other hand, the mechanism of delivering the biosensors and the mechanism for connecting the connection terminals of the biosensor and the connectors of the sensor cartridge disclosed in JP 2510702Y are both simple. Accordingly, it is thought that the problems of high manufacturing costs, of susceptibility to failure, and of being not able to perform measurement stable can be solved by using the sensor cartridge disclosed in JP 2510702Y.
In the case of using the sensor cartridge disclosed in JP 2510702Y, however, it is necessary to connect the sensor cartridge and the measurement apparatus via the distribution cable as described above, and this results in the problem of poor handleability for the user.